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UPDATE # 102 - December 13, 1999 PART 1: Upcoming Event UPCOMING EVENTS
Most classrooms are not in session for the next two weeks, so I will take a brief recess and post Update #103 on or around January 3. Opportunities in the meantime to interact with STO include: ->Tuesday, December 14, 11a.m. - noon PST QuestChat with Karl Sabbagh, writer, producer and director of Space Station, a special two part documentary airing on PBS on December 14 and 21. To attend or leave questions go to: http://quest.arc.nasa.gov/chat/prj_sto/12-14-99ks/main/chat.cgi ->Wednesday, December 15, 10-11a.m. PST QuestChat with Michael Ciannilli, who co-hosts the Landing to Launch series. On his job he monitors all of the systems on the orbiter as they are tested, and addresses any problems that as they occur. He also supports a wide variety of shuttle upgrades and the next generation of launch vehicle studies. To attend or leave questions early go to http://quest.arc.nasa.gov/space/events/ksc99/ ->Wednesday, December 22, 1999 10-11:30am PST "Tour the International Space Station" The Space Vehicle Mockup Facility in Houston, Texas is the center for manned spaceflight and headquarters for the International Space Station Program. The audience will be given a LIVE tour of the International Space Station trainers, Space Shuttle mockups, Underwater Neutral Buoyancy Labs and Centrifuges. You will get inside the Living Quarters where Astronauts will spend their work, play, rest and recreation time aboard the ISS. "Tour the International Space Station" http://quest.arc.nasa.gov/ltc/sto/tours/index99.html I wish for you a restful holiday, a very happy Christmastime and a safe and enjoyable ushering in of the year 2000! Linda Conrad THIS WEEK'S PUZZLE CHALLENGE There are two online clues this week: one that was available after the Updates and a new one for this week. Here's the puzzle 4 clue: Where are we? Identify and locate the facility in the picture. State what is so "new" about it. Points possible 5. Puzzle 5 clue: Look at these 2 pictures carefully. Identify the differences. What was done to produce these changes and when did it happen? Deadline for answering both questions is Monday, December 20. http://quest.arc.nasa.gov/space/events/ksc99/puzzle Puzzle is based on a java applet, so there might be a delay in loading. [Editor's note: Craig is a ISS Microgravity Sciences Requirements Manager. In his job he works on issues concerning the microgravity environment that exists on the International Space Station, like making sure payloads are "comfortable." ] THE CHALLENGE OF MEETING MICROGRAVITY REQUIREMENTS http://quest.arc.nasa.gov/space/team/schafer.html December 7, 1999 Interviewer: Lori Keith For my main job responsibilities, NASA looks at me to be the expert regarding the requirements the scientists need to do their research. I'm part manager, part engineer, part scientist and part diplomat. The research community (the principal investigators/scientists whose experiments will be on the ISS) and the ISS program are looking to me to be a problem solver. Many times, I am a liaison between the two. The ISS program promises the research community a certain microgravity environment. So, I must be knowledgeable in several areas to make sure all requirements are met -- like structural dynamics, space physics, and how the different managerial processes work, just to name a few. Vibrations (or what we call accelerations) are all around on the ISS, and are also called G-jitters. G-jitters can affect what's in the surrounding area, like payloads/experiments. We must determine how much vibration is allowable and how to keep it at that acceptable level. Sometimes things must be redesigned to meet the requirements, and others have to be modified with other pieces. Case in point: the exercise bicycles make a lot of vibrations, which cannot be helped, so vibration isolation systems (like a shock absorber) had to be designed, built and fitted to the exercise equipment to lower the vibrations emitted. Some of the payload racks are equipped with their own shock absorbers, called ARIS, or Active Rack Isolation System. There are computer sensors on the rack that help measure degrees of movement. The racks are attached to the station structure by eight push rods that are connected to actuators, so they can move back and forth. When the computer senses movement, it tells the push rods to move in the opposite direction, lessening the vibration, kind of like a push me/pull me routine. This allows the racks to move in "six degrees of freedom" -- moving along X, Y and Z; and rotating along X, Y and Z. This is also referred to as 6DOF, for short. These racks are used for payloads that require really low microgravity levels. I also spend a lot of time working on payload microgravity requirements. This involves structural dynamics -- how the vibration of one rack affects the others around it. In the end, an allocation scheme must be developed covering the allowable vibration limits for all the racks and each attached payload. The rack developer will determine the allowable requirements for the individual experiments housed in them. Of course, writing these requirements is a whole process on its own. It's almost like lawyer language -- for example, the word "shall" means that's the requirement, though "must" and "will" are used sometimes, too. Once the structural dynamics and the requirements are figured out, then we must make sure we are actually meeting the needs of the research community to do their research. The three of these together is when the diplomat sometimes comes into play. Though NASA thrives on teamwork that doesn't mean it's always easy when you are working with several different groups of people, in different locations. I am also working with the ARIS, which we talked about earlier. Besides the eight push rods holding the racks in, each rack also has what is called an umbilical (which is a line of connectors), to attach to the power sources of the ISS - power, communications, fluid, gas, or whatever is necessary. Though we have tested these racks on the ground in a simulated environment, we won't really know how they work until we have tested them on orbit, on the ISS. The first rack of this kind will go up on ISS Flight 6A. We will perform a test we call the ARIS ICE, which is the ARIS ISS Characterization Experiment. During this experiment, we will test the rack's movement over the six degrees of freedom, to see if the ARIS properly isolates the payloads. I am also a part of the Microgravity Analysis and Integration Team (MGAIT), which is a global team from all the member space agencies, who predicts microgravity environments for the ISS. We use computer modeling to do this. This is a big help, and can alert us to areas that might have problems later. I am hoping to chat with you all in January, so look for me on the schedule soon. [Editor's note: Steve Sokol, our STO Weather expert at Johnson Space Center, forwarded this message to us (it did not originate with him) - but I didn't want you to miss it!] LAST LUNAR HURRAH OF THE MILLENNIUM
This year will be the first full moon to occur on the winter solstice, December 22, commonly called the First Day of Winter, in 133 years. Since the full moon on the winter solstice will occur in conjunction with a lunar perigee, the point in the moon's orbit that is closest to Earth, the moon will appear about 14 per cent larger than it does at apogee, the point in its elliptical orbit that is farthest from the Earth. The Earth is also several million miles closer to the sun than in the summer, and sunlight striking the moon will be about 7 per cent stronger making it brighter. Also, this will be the closest perigee of the Moon of the year, since the moon's orbit is constantly deforming. In layman's terms, it will be a super bright full moon, much more than the usual AND it hasn't happened this way for 133 years. If the weather is clear and there isn't a snow cover where you live, it is believed that even car headlights will be superfluous. Our ancestors 133 years ago saw this. Our descendants 100 or so years from now will see this again. Remember, this will happen December 22, 1999. STATUS OF ORBITER PROCESSING - PREPARING FOR STS-103 Typically this area is devoted to processing of the Columbia Orbiter. At this time Columbia is in California so we will continue to use this area to update you on the mission in focus, in this case STS-103, the Hubble Servicing Mission: Workers noted a dent in the line during routine aft compartment inspections Tuesday the 7th. The dent measures 12 inches long and about *-inch deep. The line recirculates hydrogen from the Shuttle main engines back to the external tank during prelaunch engine conditioning. The section of this manifold line that requires replacement measures about 6 feet long. A spare hydrogen recirculation line has already been prepared for installation. Tomorrow morning, workers at Launch Pad 39B will begin work to remove the damaged line. Under the current plan, installation of the replacement line begins Saturday and orbiter aft compartment close-outs will occur on Monday. At Launch Pad 39B, preparations to replace Shuttle Discovery's dented main propulsion system liquid hydrogen recirculation line are complete. Over the weekend, workers at Launch Pad 39B completed inspections and leak checks on Shuttle Discovery's replaced liquid hydrogen recirculation line. Engine compartment close-outs started Sunday and are expected to conclude later today. Launch managers at KSC plan to begin the 43-hour countdown Tuesday at 1:30 a.m. EST. Weather forecasts indicate an 80 percent chance of favorable weather conditions for Thursday's launch attempt at 9:18 p.m. Processing Milestones: Aft engine compartment closed-out for flight. . . . . . . . (Dec.13) Launch countdown clock begins . . . . . . . . . . . . .(Dec.14 at 1:30a.m.) Cryogenics loaded in Discovery's onboard storage tanks . . .(Dec. 15) Rotating Service Structure moved to park position . . .(Dec. 16 at 2:30a.m.)
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